1. Vaccine trials
on AIDS

2. Contents
• What is AIDS?
• Need of AIDS vaccine
• How might an AIDS vaccine work
• Difficulty in developing AIDS vaccine
• Organizations
• Clinical trials
• References

3. • Aids stands for Acquired Immune Deficiency Syndrome
• It is caused by HIV virus (Retrovirus) which attacks the
immune system cells.
• It is transmitted through bodily fluids ,sexual
contact, sharing needles, mother to the baby.
• Aids was first identified in the early 1980s.

4. Why do we need an AIDS
vaccine? ??
 Today, there are an estimated 33.4 million people living
with HIV and AIDS
• Children could be given an HIV and AIDS vaccine before
being exposed to the HIV virus, and this would protect
them from all routes of HIV transmission.
• Vaccinating large numbers of people would be much
simpler and cheaper than providing antiretroviral
treatment for those already infected.

5. Is there an AIDS vaccine?
No
An AIDS vaccine does not exist yet.

6. How might an AIDS vaccine work?
• It can be effective in two ways one can be
therapeutic vaccine and other would be preventive
vaccine.
• An effective aids vaccine would teach the body to
recognize HIV and provoke an immune response that
would defend the virus if it entered the body.
• The information on how to fight the immune system
would become part of immune system’s memory and
our body would be prepared to fight back.
• Live attenuated and live-recombinant vaccines are
able to fully activate the immune system

7. Approaches towards AIDS
vaccine…….
DNA vaccines:
Synthetic copies of HIV genes are injected into the
body resulting in the production of antigens that
hopefully can produce a strong immune response.
Bacterial and viral vector vaccines:
• Copies of HIV genes are inserted into weakened
bacteria or viruses that do not harm humans.
• These bacteria or viruses carry the synthetic HIV
genes into the body to induce an immune response.

8. Contd……
Other approaches:
It includes peptide vaccines, Pseudovirions and
combinations of vaccines with adjuvants that can boost
immune responses.

9. Why is it difficult to develop an AIDS
vaccine?
• HIV destroys the immune system cells that are meant to
fight against it .
• Soon after infection, HIV inserts its genetic material into
human cells, where it remains hidden from the immune
system.
• HIV occurs in several subtypes, each of which is very
different from the others.

10. Contd….
• Even within each subtype, HIV is highly variable and
constantly changing.
• There are no good animal models to use in experiments
although the use of non human primate (NHP) models
could become a more significant model for HIV vaccine
design and testing in the future.

11. Phases of Testing HIV Vaccines
The three phases of HIV vaccine clinical trials are:
• Phase I involves small number of healthy volunteers to test
the safety of various doses.
• Phase II testing generates additional safety data as well as
information for refining the dosage and immunization
schedule. The efficacy is tested in Phase IIb trial.
• Phase III involves thousands of volunteers to test safety and
efficacy.

12. Organizations sponsoring HIV vaccine
research.
• HIV Vaccine Trials Network (HVTN)
• International AIDS Vaccine
Initiative
• VaxGen
• National Institute of Allergy and
Infectious Diseases (DAIDS).
• Merck & Co.Inc
• AIDS vaccine advocacy coalition
(AVAC)

13. Clinical trials

14. tgAAC09 Vaccine
The purpose of this study is to determine safety and
immunogenicity (ability to induce an immune response)
of a novel HIV vaccine based on adeno-associated virus
(AAV).
Sponsors: International AIDS Vaccine Initiative.
Study Design :
Allocation: Randomized
Control: Placebo Control
Endpoint Classification: Safety

15. Contd…………
Masking: Double Blind
Primary Purpose: Prevention
Eligibility
Age:18 - 50 Years
Gender: Both
Healthy Volunteers: Yes
Inclusion Criteria:
• Healthy males and females.
• Men or women between 18 -50 years of age.
• HIV-uninfected and at low risk for HIV infection.
• Available for follow-up

16. Contd……..
• Literate, who can give written informed consent
• Willing to avoid pregnancy
Exclusion Criteria:
• HIV- infected or practicing high risk behaviour for HIV
infection.
• Pregnant or lactating women .
• Presence of chronic disease, mental disorders and
physical disability.
• Recently received vaccine, blood or blood products.
• History of allergic reactions to vaccination.

17. Contd………
Results :
• In this trial ,HIV specific T-cell mediated immune response
were observed.
• However antibody response was not observed.
Conclusion:
• The trial was a benchmark in phase I clinical evaluation of
HIV candidate vaccines in India.
• The vaccine was generally well tolerated and raised no
safety concerns.
• The vaccine was found to be weakly immunogenic

18. List of clinical trials
MRKAd5 HIV-1 gag/pol/nef :
• Objective: This study is done to determine whether
MRKAd5 HIV-1 gag/pol/nef vaccine followed by
treatment interruption can increase immune system
function in adults with acute or recent HIV infection
who have started taking anti-HIV drugs.
• This was a randomized, double-blind, placebo-controlled
Phase IIb trial.
Sponsor:
Merck & Co. Inc. (Whitehouse, NJ) and the National
Institute of Allergy and Infectious Diseases (NIAID)

19. Result:
• The vaccine did not work. It did not prevent HIV
infection and neither induce HIV-specific cell –
mediated immunity.
• It also did not reduce the amount of virus in the study
participants who were infected.
.

20. The HVTN 503 (Phambili) HIV Vaccine
• Objective: The HVTN 503 ("Phambili") study was
designed to evaluate the safety and preliminary efficacy
of the same Merck HIV candidate vaccine tested in the
HVTN 502 STEP study, but it is being conducted in
South Africa
• This is a randomized, placebo-controlled, double-blinded
Phase IIb trial

21. RV 144 (ALVAC / AIDSVAX )
• Objective: The purpose of this study is to determine
whether immunizations with an integrated combination
of ALVAC-HIV (vCP1521) boosted by AIDSVAX gp120
B/E prevent HIV infection in healthy Thai volunteers.
• This was a randomized, placebo-controlled, double-blinded
Phase III trial.
• Sponsor: U.S Army Medical Research and Material Command

22. What vaccines were used in the study?
• ALVAC‐HIV (vCP1521) consists of a viral vector containing
genetically engineered versions of three HIV genes
(env, gag and pro). The ALVAC vector is a disabled form of
bird virus called as canary pox.
• AIDSVAX B/E is composed of genetically engineered gp120.
Result:
• The vaccine regimen is safe and 31.2 % effective at
preventing HIV infection.
• While this is a modest level of efficacy, it represents a major
step forward for HIV vaccines, providing the first evidence
that development of a safe and effective preventive HIV
vaccine is possible.

24. References
 http://www.avert.org/aids-vaccine.htm
 http://clincaltrialsfeeds.org
 http://clinicaltrials.gov
 http://en.wikipedia.org/wiki/HIV_vaccine
 http://www.cgdev.org/section/search?q=aids+vaccine
 http://www.hvtn.org
 http://www.stepsstudies.com
 http://www.avac.org
 http://www.nari-icmr.res.in/